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Centromere that plays a pivotal role in chromosome segregation is composed

Centromere that plays a pivotal role in chromosome segregation is composed of repetitive elements in many eukaryotes. the left arm proximal to cen3, whereas the strain background, the presence of ChL is usually manifested as Leu+ Ura+ Ade+. When GCR associated with a specific loss of the region encompassing the … Table 1 Rates of GCR and minichromosome loss in the wild-type, and strains Two different types of GCR products are detected using ChL minichromosome To determine the kind of chromosomal rearrangement occurring in this system, chromosomal DNA was prepared from 15 impartial clones of Leu+ Ura? Ade? and the parental strain, separated by pulse field gel electrophoresis (PFGE) and stained with ethidium bromide (EtBr) (Physique 2BCD, left panels). The lengths of the minichromosomes in Rabbit polyclonal to AREB6 Leu+ Ura? Ade? clones were different from that of the parental ChL, indicating that GCRs rather than simple GCs or point mutations have occurred in these clones. To characterize the GCR products, the separated DNA was transferred onto a nylon membrane and hybridized with specific probes shown Typhaneoside supplier in Physique 2A (Physique 2ACD). All the minichromosomes were detected using probe LEU2 (Physique 2B), showing that they are derived from ChL. However, only the parental ChL was detected using probe ura4 or ade6 (Physique 2B and C), showing loss of the two markers in the GCR clones. It was found that half of the rearranged minichromosomes contained regions A, B, C, and D, as well as rDNA that is originally present at the ends of ChIII, and were longer than ChL (Physique 2E, type-I GCR). On the other hand, the others experienced lost regions A and B, and were smaller than ChL (Physique 2E, type-II GCR). None of the minichromosomes contained region E or F that is specific to the ChIII left arm. These results show that two different types of GCRs are detected in this system. Figure 2 Analysis of chromosomes by PFGE. (A) Positions of the probes used in Southern hybridization are indicated as packed boxes under ChIII and ChL. The name of the gene or ORF that is overlapping or nearby the probes ACF is usually shown above ChIII. (BC … Translocation between homologous chromosomes ChL and ChIII To determine the position where the translocation occurred in type-I GCR products, we introduced an additional marker, the gene, on the right side of cen3 (Physique 3A). The introduction of did not impact the chromosome stability (Supplementary Table I), and around half of the GCR products were type-I determined on the basis of the minichromosome length and the presence of region D (Figures 2 and ?and3B).3B). Re-hybridization with a probe specific to showed that 10 of the 12 type-I products retained the marker. These results suggest that in most cases type-I products are created by translocation within the region flanking cen3 and gene on the right side of cen3. The gene was launched between and (observe Materials and methods). (B) Chromosomal DNA … Formation of isochromosome produced round the centromere To define the length of the type-II GCR products, PFGE was carried out under the condition where 50C800 kb DNA can be resolved. Assuming DNA ladder as a standard, it was decided that type-II products were 330C400 kb, whereas ChL was 540 kb (Physique 4A). As the length of the ChL left arm plus the centromere Typhaneoside supplier is usually 220 kb (Physique 1A), type-II products seem to have Typhaneoside supplier acquired some DNA sequences of 110C180 kb. In an attempt to identify the sequence, the minichromosomes were recovered from your gel and subjected to comprehensive genome hybridization (CGH) using oligonucleotide arrays. When ChL was used as a probe, 500 kb around cen3 was detected, as expected (Physique 4B, ChL; Supplementary Physique 1). However, other than the original left arm and cen3, no consecutive sequences of >100 kb were detected using a type-II product (clone no. 1) (Physique 4B, type-II; Supplementary Physique 2). Similar results were obtained using several other type-II products (clone no. 4, 8, and 11, observe Supplementary Physique 3) that are different in the length from each other and from clone no. 1. Detection of.